| Computer Code: |
GRN |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Brigantian Substage (CX)
— Brigantian Substage (CX) |
| Lithological Description: |
[Obsolete: use CLWYD, CRAV]
Limestones and dolomites with cherts overlying dark limestones with mudstone partings. |
| Definition of Lower Boundary: |
Drawn at the base of the Teila Formation at Prestatyn where dark fine-grained argillaceous mudstones rest unconformably upon reef limestone. |
| Definition of Upper Boundary: |
Drawn at the conformable upward passage of the Pentre Cherts where cherts with thin calcite and dolomitic beds are conformably overlain by fossiliferous mudstones. |
| Thickness: |
145 metres - 180 metres. |
| Geographical Limits: |
Areas around Prestatyn and Great Orme. |
| Parent Unit: |
none recorded or not applicable
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Area |
Prestatyn and Great Orme. |
| Reference(s): |
| George, T N. 1974. Lower Carboniferous rocks in Wales. 85-115 in The Upper Palaeozoic and Post-Palaeozoic Rocks of Wales. Owen, T R, (editor). (Cardiff: University of Wales Press.) |
| Definition not published. |
| George, T N, Johnson, G A L, Mitchell, M, Prentice, J E, Ramsbottam, W H C, Sevastopulo, G D, and Wilson, R B. 1976. A correlation of the Dinantian rocks of the British Isles. Special Report of the Geological Society of London, No. 7. |
| Somerville, I D, 1979. Minor sedimentary cyclicity in Late Asbian (Upper D1) Limestones in the Llangollen district of North Wales. Proceedings of the Yorkshire Geological Society, Vol.42, p.317-341. |
| Ramsbottom, W H C, 1984. The Lower Carboniferous (Dinantian). p.107-127. "In" WARREN, P T. and others. Geology of the country around Rhyl and Denbigh. Memoirs of the British Geological Survey, Sheets 95 and 107. (England and Wales). |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E094
|
